To improve turning performance and emergency obstacle avoidance performance of a vehicle, a known 4-wheel steering device includes 4-wheel steering mechanisms for regulating wheel turning angles of the four wheels to achieve a maximum avoidance performance in the event of an emergency. In addition, a drive controller is known that utilizes a difference in a driving force between the left and the right wheels for yaw rate control when making a turn. Examples of such drive controllers may be found in Japanese patent application nos. 5-238403 and 10-210604.
However, in a typical vehicle including the aforementioned conventional technology, the vehicle is designed to have an understeering property up to a low oversteering property. Thus, its yaw motion performance is lower than that of a vehicle with a high oversteering property when the center of gravity is placed toward the rear of the vehicle, for example. Accordingly, there is still a further need for improvement for turning and avoidance performance in a variety of vehicles.